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Discussion Starter · #1 ·
As I prepare for the upcoming season, I realize that I read about hitting the tires too hard but I haven't found a good explaination of how to tell if you are hitting the tires too hard. Anyone have a good definition and way to determine if you are hitting them too hard or too soft??
 

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With 1.43 60fts and a 9.74 ET my guess is wasted motion . I'll bet your IC location is close to stock and too violent.
This issue has been hashed , smashed and beat to death on web sites but it appears clearly that even in Chevelles , they will benefit from relocated ICs down and forward , stiff springs and double adjustable shocks........probably exactly what the Wiebe suspension does.

Your 60s SHOULD be in the mid to high 1.30s

Video video and more video........
 

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It's not so much hitting the tires too hard as it is incorrect suspension geometry, springs, and shocks. These cars need to strike the tire extremely hard but then keep the tire planted. Keeping the tire planted is the problem with the stock setup no matter how you go about it. The stock setup tends to give up just a few feet off the starting line and lets the tire recoil back up into the wheel opening thus unloading the suspension. This is usually mistaken as hitting the tire too hard, and can be bandaided by hitting the tire softer but even with the correct IC on the stock suspension you will never get rid of the tendancy for it to want to unload. The stiffest spring you can find, and some good double adjustable shocks will help. And I mean good doubles, like Afco, which are real pricey. At your power level it is going ot be real hard to to get the thing to settle down with the stock setup. You may have to let it turn the tire a bit, but to get it to dead hook and be consistent may be a bit of a chore, especially on a less than perfect track.
 

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Discussion Starter · #5 ·
Great article Rodger. Thanks, that is the first one I've read which actually talks about how to attack the adjustments.
Chad, I tried my Weibe suspension last year and never got good results. I'm going to go back to my stock set up this spring which is tunable. The Weibe set up is not and until I can discuss it in detail with Alf I'd like to continue working with my stock set up which is ; Morrison no-hops which give me upper arm adjustment, I built upper arms which are adjustable and have heim joints on both ends, Adjustable lower arms by Wolfe Craft which also have heim joints on both ends, Wolfe Craft anti-roll bar, I have fabricated front mounts for my lower control arms which will allow for vertical adjustment of the front mount location similar to a four link bracket, and yes I've invested in a set of AFCO shocks.I also went to 28 x 10.5 stiff M/T's on 9" rims to better match my tires to the rim width. ( I was on 29.5 x 10.5 Stiffs on an 8" rim )
I agree the recoil of the rear axle is a challenge and I'm hoping the AFCO's will help with that as well as less anti squat.
We'll see.
 

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What was the issue with Alf's suspension? What shocks were you running up front and on the rear. How about front springs?
 

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Discussion Starter · #7 ·
It just blew the tires off. I tried leaving as low as 2200 RPM , lower and higher air etc. I tried the Koni's that came with it as well as my QAL's . Granted our track is not very well prepped but it just didn't work. I checked it for binding etc..and there was none. Pretty frustrating as others swear by it but it didn't work for me. Maybe because I leave off of a break and a delay box. don't know. The kit , which I purchased used ,came with the really, really stiff springs. You couldn't even bounce the rear end.
 

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What is in use on the front of the car? Alf's stuff is tunable, via preload and shocks. The front set up is just as important as the rear........ Have you tried footbrake launch with the car?
 

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Discussion Starter · #10 ·
Sorry, I forgot the front end. I have TRZ control arms w/ Strange double adjustable coil overs. Weight bias is 55% front 45% rear w/o ballest. I have about 5" of travel @ the wheel wells. I didn't mess with preload as the car launched straight, just spun bad. I didn't try foot braking as we only have one class and with a sportsman tree a delay box really helps keep me competitive.
 

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Great article Rodger. Thanks, that is the first one I've read which actually talks about how to attack the adjustments.
Chad, I tried my Weibe suspension last year and never got good results. I'm going to go back to my stock set up this spring which is tunable. The Weibe set up is not and until I can discuss it in detail with Alf I'd like to continue working with my stock set up which is ; Morrison no-hops which give me upper arm adjustment, I built upper arms which are adjustable and have heim joints on both ends, Adjustable lower arms by Wolfe Craft which also have heim joints on both ends, Wolfe Craft anti-roll bar, I have fabricated front mounts for my lower control arms which will allow for vertical adjustment of the front mount location similar to a four link bracket, and yes I've invested in a set of AFCO shocks.I also went to 28 x 10.5 stiff M/T's on 9" rims to better match my tires to the rim width. ( I was on 29.5 x 10.5 Stiffs on an 8" rim )
I agree the recoil of the rear axle is a challenge and I'm hoping the AFCO's will help with that as well as less anti squat.
We'll see.
If you want to sell it, My friend Steve is looking to buy one.

I dont see why it wont work with a Transbrake, the stocker has the same setup and it leaves off a two step. hits the tires very similarly.

It might have something to do with the coil over setup....i'd definetly use a factory front spring if you can.

here's why:

take an 18" tall spring, and compress it to about 9" and you have ALOT of stored energy:

I'll make a chart.

Lets say that your front end weighs for conversation 1800lbs.

with an 18" tall spring at 220lbs per inch
it will compress to 10"

at 10" it has roughly 1780lbs on it (based on the ratio of our control arms

as the front end starts to extend:

at 1" of extension it has 1560lbs of pressure on it

at 3" it has 1120lbs

at 5" it has 680lbs....then your front tire is yanked off the ground.



Now lets look at the typical spring for a Qa1 shock:

350lbs/in....they're going to compress 5" with 1780lbs of load on them

at 1" of travel they're putting 1430lbs of pressure back on the chassis

at 3" 730lbs

at 5" 30lbs
 

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Cash in hand :D
 

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I'd say the problem in a nut shell lies solely up front. These cars don't need anything fancy up front. Koni shocks, Afco's if you want to spend the money, and a moog spring around 260-280 lbs/inch that will give you around 4.5-5" of travel with the stock upper bump stop. I believe Kjett can tell you all about the aggrevation of a coil over front end setup.
 

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With 1.43 60fts and a 9.74 ET my guess is wasted motion . I'll bet your IC location is close to stock and too violent.
This issue has been hashed , smashed and beat to death on web sites but it appears clearly that even in Chevelles , they will benefit from relocated ICs down and forward , stiff springs and double adjustable shocks........probably exactly what the Wiebe suspension does.

Your 60s SHOULD be in the mid to high 1.30s

Video video and more video........
It kind of depends on the RPM of the leave and whether or not you footbrake. About 1.40 is a more normal sixty if you have a moderate 4000 stall converter, 4.10 gears, and the car weighes in the 3800 pound range. Once the car gets into the 1.30s it's leaving very well. Light cars can exceed this by quite but not barges like most '70-'72 Chevelles. I think the key to the suspension not doing it's job is probably due to poor track conditions. They held a mock street type race here at Tulsa and didn't VHT the track "at all". We had had some poor weather in the week leading up to the race and that no doubt contributed to the problems but nobody could get any bite and three cars hit the wall at that race. Most spectators tired of the poor track conditions and several street squirrels, (3), lost nice cars from being stupid and running on an unprepared track. Nobody should try to race a fast car on a bad track.
 

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Discussion Starter · #19 ·
well I'm a little stuck as I modified the spring pockets to accept the coil over setup. :(( See earlier picture ) Any ideas how to get more stored energy with the coil overs?? I'm using a 12 " spring @ 425#'s over strange shocks.
Would a softer spring with more initial compression be better??
I'm going to keep the Alf set up until I figure out what is going on. If it truly is the front end then I'll go back and try the Alf setup again once I get it sorted out.
 

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Maybe this will help some and maybe it won't??? My nova weighs in at 3,500 lbs which 60 ft's in the 140's which I thought was not bad..I have a 110 spring in the rear with afco's..Up from I run a six banger spring that's rated in the 280-290 range with a set of 90/10 shocks. When I 1ST got the car it had a hooking problem and to find out it had a rated 275 spring in the rear which was way to stiff.I tried a 130 spring as well but it really like's the 110 spring better.I would start by trying a couple of different rated spring's in the rear.
 
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